Hi guys,
I'm not sure I'm posting it on a right section, if not please move it.
So my problem is:
I built the "poor man's surround" system on the other day with 2.1 pc speaker + 2.0 system (cut out the 2.0 amp and re-wired accordingly the haflers circuit). But, volume on the rear speaker are extremely low.
Is it possible somehow re-implement the 2.0's amp to amplifie the rear speakers?
I'm open to other solutions as well.
I'm not sure I'm posting it on a right section, if not please move it.
So my problem is:
I built the "poor man's surround" system on the other day with 2.1 pc speaker + 2.0 system (cut out the 2.0 amp and re-wired accordingly the haflers circuit). But, volume on the rear speaker are extremely low.
Is it possible somehow re-implement the 2.0's amp to amplifie the rear speakers?
I'm open to other solutions as well.
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Let me get this right, you are talking about the ~1970 "Hafler-Dynaco" Quad adaptor ambience system ( a couple of Caps and resistors to connect a pair of rear speakers across +L and +R output terminals?
If so, the output level depends on the stereo difference between channels so some program will have almost no output as will central sources like the main vocalist, instrumentalist or bass. Phase correction is dependent on the resistors which further reduce output but as "ambience" speakers, they were not expected to be noticeable - just "there". I built a couple of boxes for this many years ago and even with high sensitivity speakers, the results weren't worth it. - too low an output with modern recording and sound mixing practice.
If you just want more volume, the rear speakers have to be boosted with another pair of amplifiers but this also requires a filter that mimics the system of in the original design. This is at preamplifier level, so small components can be used with higher impedance to suit the inputs. Really though, you are looking for a surround sound adaptor and that can be expensive.
Have a look at this project and the introductory details: http://sound.westhost.com/project18.htm
If so, the output level depends on the stereo difference between channels so some program will have almost no output as will central sources like the main vocalist, instrumentalist or bass. Phase correction is dependent on the resistors which further reduce output but as "ambience" speakers, they were not expected to be noticeable - just "there". I built a couple of boxes for this many years ago and even with high sensitivity speakers, the results weren't worth it. - too low an output with modern recording and sound mixing practice.
If you just want more volume, the rear speakers have to be boosted with another pair of amplifiers but this also requires a filter that mimics the system of in the original design. This is at preamplifier level, so small components can be used with higher impedance to suit the inputs. Really though, you are looking for a surround sound adaptor and that can be expensive.
Have a look at this project and the introductory details: http://sound.westhost.com/project18.htm
I follow this description:
How to add Surround into a plain stereo system - Everything2.com
So basicly I just connected my 2 spare pc speakers between the +L +R in the 2.1 amp.
Now I have a spare amp circuit from it and I wonder can I use it somehow to amplify the rear speakers, connect it parallel or in series, just not sure how exactly.
Unfortunatly I can't open your link, its loading endlessly.
I'm not looking for a surround sound adaptor (atleast not right now) just I like to re-use old stuff and build something useful.
How to add Surround into a plain stereo system - Everything2.com
So basicly I just connected my 2 spare pc speakers between the +L +R in the 2.1 amp.
Now I have a spare amp circuit from it and I wonder can I use it somehow to amplify the rear speakers, connect it parallel or in series, just not sure how exactly.
Unfortunatly I can't open your link, its loading endlessly.
I'm not looking for a surround sound adaptor (atleast not right now) just I like to re-use old stuff and build something useful.
Go here:
AK Database PDF Gallery - Dynaco/Dynaco ST120 Assembly/Owner's Manual
Download the Dynaco St120 assembly manual PDF.
Then go to page 6 for the Speaker wiring diagram for the "quad ' setup.
A simple early Hafler invention... No extraneous parts required.
AK Database PDF Gallery - Dynaco/Dynaco ST120 Assembly/Owner's Manual
Download the Dynaco St120 assembly manual PDF.
Then go to page 6 for the Speaker wiring diagram for the "quad ' setup.
A simple early Hafler invention... No extraneous parts required.
Page 6 shows just another variation of the OP schematic discussed here. The only volume controls I have seen in these simple, unamplified arrangements is a 20-100R wirewound pot. or fixed resistors in series with the rear speaker pair or that centre, bridging speaker (if used).
In a local variation I saw at the time, 220 uF capacitors were used, connected in a non-polarised arrangement, to give some rear speaker phase shift. The volume was reduced further but you could hear a more believeable sound. Obviously, you can't increase volume this way in a passive circuit and there is going to be some interaction of controls.
In a local variation I saw at the time, 220 uF capacitors were used, connected in a non-polarised arrangement, to give some rear speaker phase shift. The volume was reduced further but you could hear a more believeable sound. Obviously, you can't increase volume this way in a passive circuit and there is going to be some interaction of controls.
Which ESP shematic are you referring to? Both fig.2 & 3 schematics operate at line level (input signal plug level) and require amplification with, for example, your original set of powered speakers you described as "cut out".
Just reconnect the speakers in your original 2.0 system to their amplifier. You then have adjustable volume rear speakers when you connect the adaptor between the input signal and the 2.0 input socket. Note: you have to add shielded wiring to connect the signal from the 2.1 system input socket to do this.
I'm talking about the schematics 3.
I think I get what you saying.
But one more thing, my 2.1 system's amp is inside the sub-woofer box. So the input to this adaptor come from the box, how should I connect the sub to the output at the same time? Or just leave it that way?
Maybe I'm not so clear, Later I draw something to express how I imaging this.
Also thanks for your help, I'm really appreciate it
Sorry if I'm asking lame things
I think I get what you saying.
But one more thing, my 2.1 system's amp is inside the sub-woofer box. So the input to this adaptor come from the box, how should I connect the sub to the output at the same time? Or just leave it that way?
Maybe I'm not so clear, Later I draw something to express how I imaging this.
Also thanks for your help, I'm really appreciate it
Sorry if I'm asking lame things
Perhaps you misread the diagram. (ESP P18, fig3.) The Main in-out connectors allow you to plug your signal source into the adaptor and also connect to your existing 2.1 system.
The diagram shows RCA sockets where earth is the outer circle shown. All earth connections are common and connected together. The L and R channel + connections (centre pin) are simply the same input for both the 2.1 and 2.0 systems. The centre pins are not connected to earth, so that's why 2 sockets in parallel for each channel - as an adaptor to connect input to both front and rear systems, right?
You can leave the 2.1 system as it is and and omit the Sub and centre channel connections of the adaptor. You already have the sub adaptor. In fact, you can omit the whole lower half of the circuit and R3,4 as well. You can use just a TL071 op-amp to make it simple.
You can use 3.5mm stereo jack sockets, if you want to. However, use shielded wiring as it comes with a stereo jack plug/plug extension lead or any stereo lead. Don't use 3 separate wires for connecting leads. You need an earth shield to the signal leads of, R & L channels and this is always necessary to minimize hum and noise.
The downside of 3.5 mm audio plugs is that the connections made with them can be noisy and if cables are moved, can make crackling noises. They are not the best for stereo separation either and that is why they are only used with miniature personal devices like radios, iPODs, MP3 players etc. Take care if using these as your input since their outputs are intended for headphones or earbuds. The devices often don't produce enough output voltage for amplifiers and means cranking the control up or needing to use higher amplifier volume settings. Overall, this increases noise levels.
Try to obtain the most suitable stereo socket type that either mounts on your circuit board (perhaps vero or stripboard) or, with very short leads only, connect as you say with 3 wires to an old style stereo panel mount (metal) type.
The downside of 3.5 mm audio plugs is that the connections made with them can be noisy and if cables are moved, can make crackling noises. They are not the best for stereo separation either and that is why they are only used with miniature personal devices like radios, iPODs, MP3 players etc. Take care if using these as your input since their outputs are intended for headphones or earbuds. The devices often don't produce enough output voltage for amplifiers and means cranking the control up or needing to use higher amplifier volume settings. Overall, this increases noise levels.
Try to obtain the most suitable stereo socket type that either mounts on your circuit board (perhaps vero or stripboard) or, with very short leads only, connect as you say with 3 wires to an old style stereo panel mount (metal) type.
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In post #13, I mentioned you could use just a TL071. That is a single OP-AMP, the TLO72 is a double. Yes, you can use only half the TL072 or build the whole circuit if you wish but look at your inputs and outputs - they are already for stereo, so you don't need any more than what you see in the schematic.
Read #13 again. If you are having trouble understanding, say so. I am restating here that you only need 1 op-amp for both channels if you don't require either a centre channel or a second subwoofer adaptor. Look at the connections for the rear channels - note they both derive from only the top op-amp. The bottom op-amp is only needed for the subwoofer and centre channel adaptors which are mono.
i.e. Use one, single opamp (shown as the the top half of the circuit - one single circuit - one single TL071 - nothing more).
Remember, this an adaptor, not an amplifier so your 2.0 system is necessary to provide the power to drive the speakers.
Perhaps it is unclear but the OP-amps shown in the schematic are both in one package - called TL072.
You only need half that number of op-amps and that type of opamp with a single one is called TLO71.
Both types are available in the same 8-pin DIL package but with different connections
Read #13 again. If you are having trouble understanding, say so. I am restating here that you only need 1 op-amp for both channels if you don't require either a centre channel or a second subwoofer adaptor. Look at the connections for the rear channels - note they both derive from only the top op-amp. The bottom op-amp is only needed for the subwoofer and centre channel adaptors which are mono.
i.e. Use one, single opamp (shown as the the top half of the circuit - one single circuit - one single TL071 - nothing more).
Remember, this an adaptor, not an amplifier so your 2.0 system is necessary to provide the power to drive the speakers.
Perhaps it is unclear but the OP-amps shown in the schematic are both in one package - called TL072.
You only need half that number of op-amps and that type of opamp with a single one is called TLO71.
Both types are available in the same 8-pin DIL package but with different connections
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Yes that's what got me, its in the same package, but the schematic show two, but I understand it now.
Anyway, I will build the whole circuit, I gathered another speaker so I try out the center channel thing. Maybe if its wont work or I wont like it I do it again, I just ordered a couple set of the materials, so I could build like 3 of this. Its a good experiment
And thanks again for you patient, I know I ask lame thing, but I rather ask now everything what is not clear to me then regret it later when something goes wrong.
Anyway, I will build the whole circuit, I gathered another speaker so I try out the center channel thing. Maybe if its wont work or I wont like it I do it again, I just ordered a couple set of the materials, so I could build like 3 of this. Its a good experiment
And thanks again for you patient, I know I ask lame thing, but I rather ask now everything what is not clear to me then regret it later when something goes wrong.
Great! I hope you have fun as I did when I tried these types of projects many years ago.
Don't be disappointed that the effects possible with such simply synthesised channels can be really weak and unrealistic compared to digitally mastered (Dolby, THX) or even analog post-delayed sound systems. This system depends heavily on the difference between L and R channels to supply signal to the rear channels. Of course, that's why all recent movies now use those newer systems.
Just correcting above post, The style is DIP, not DIL. When you need connection details, Google is your friend - type "TLO72 pinout" into your search engine browser and voila!
Don't be disappointed that the effects possible with such simply synthesised channels can be really weak and unrealistic compared to digitally mastered (Dolby, THX) or even analog post-delayed sound systems. This system depends heavily on the difference between L and R channels to supply signal to the rear channels. Of course, that's why all recent movies now use those newer systems.
Just correcting above post, The style is DIP, not DIL. When you need connection details, Google is your friend - type "TLO72 pinout" into your search engine browser and voila!
Yeah, I found it.
Also I'm glad you mentioned the delay thing, I read a couple thing about it on the ESP site you showed me. If I succeed with the adaptor I'm thinking about to add some kind of delay.
Digital Delay accord to this. But the first couple circuit is way too hard to understand for me, but there is the figure4, kinda simple. Could it work for me? Or is it more complex than I think
Also I'm glad you mentioned the delay thing, I read a couple thing about it on the ESP site you showed me. If I succeed with the adaptor I'm thinking about to add some kind of delay.
Digital Delay accord to this. But the first couple circuit is way too hard to understand for me, but there is the figure4, kinda simple. Could it work for me? Or is it more complex than I think
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